Systematic Effects in Gaia CRF Photometry Related to Scanning Geometry and BP/RP excess factor

I report a previously undocumented, large-amplitude systematic dependence of the median Gaia $G$-band magnitude of CRF3 sources on $\mathtt{\text{ra\_dec\_corr}}$, which reflects the preferred direction of scans, accompanied by a partially correlated trend in the BP/RP flux excess factor. Given the imminent release of Gaia DR4, the purpose of this note is alerting the community to this artifact.